Las Vegas, Nevada - Jennifer Lopez was the hostess with the mostest while in Vegas with Ben Affleck!

Sin City was the place to be this weekend.

The 54-year-old Lets Get Loud artist rocked two sexy fits while hosting a Las Vegas Poker Tournament with her 51-year-old hubby.

The Friday event marked the start of Formula 1's Las Vegas Grand Prix weekend, which saw several more A-list stars including Rihanna and A$AP Rocky.

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JLo first rocked a sultry David Koma cutaway gown while posing on the red carpet, which featured panels of black and bejeweled fabric with a connected choker detail and a thigh-high split.

The Monster-In-Law actor's second outfit was a skintight ruched Magda Burtrym dress with tantalizingly translucent fabric and a stunning floral design at the neckline.

Friday's event was also reportedly a fundraiser for Affleck's non-profit, Eastern Congo Initiative.

The couple's red carpet look not only turned heads but also dispelled talk that two's marriage is on the rocks, after the Oscar-winner recently had a cozy encounter with his ex-wife, Jennifer Garner.